PL204586B1 - Anti-icing solution - Google Patents

Abstract

A de-icing and anti-icing composition in the form of an aqueous solution which includes a low molecular weight carbohydrate, a inorganic freezing point depressant in the form of a chloride salt, and a thickener. The molecular weight of the carbohydrate is from about 180 to 1,500, with a preferred range of about 180 to 1,000.

Description

Description of the invention

The present invention relates to a deicing and anti-icing composition. Prior art methods for removing snow and ice from road surfaces typically employ a deicer, such as salt, to be sprinkled on the pavement. Sometimes anti-skid substances such as sand or other aggregates such as gravel are used with or without salt.

The use of salt or compositions with a high salt content is disadvantageous as they cause corrosion of vehicles, damage to the road surface, and also endanger the environment as a result of running salt water from roads, which pollutes the soil and water in the immediate vicinity.

Due to the problems presented herein with the use of salt-containing formulations, there has hitherto been a need for a deicing composition or formulation that can effectively melt snow or ice and that can reduce the corrosion and environmental pollution problems mentioned above. In order to meet the problems associated with the use of salt, the solutions known from the state of the art presented substances that allowed to reduce the intensity of corrosion and were more environmentally friendly.

U.S. Patent 5,635,101 (Janke et al.) Relates to a deicing composition containing a by-product of the wet milling process of corn in shell. Corn kernels are soaked or soaked in a hot solution containing a small amount of sulfuric acid (IV). They are then separated from the water in which they have been soaked, and this aqueous solution is used to produce the deicing composition.

U.S. Patent No. 4,676,918 (Toth et al.) Discloses a deicing composition comprising a mixture that includes at least one component selected from a plurality of chlorides or urea and an admixture of alcohol distillate waste concentrate with a dry matter content of 200 to 750 g / kg and from 10 to 80% by weight of water.

U.S. Patent No. 6,080,330 (Bloomer) further teaches a composition for preventing the formation of ice or snow on exposed surfaces, such as road surfaces or specific substance storage sites, and further for defrosting surfaces where snow or ice has accumulated. The composition is made of a by-product obtained in the recovery of sugar from sugar beet molasses, also called sugar beet molasses.

CA 2256103 discloses a deicing composition which comprises a film former, such as e.g. cellulose derivatives, modified polysaccharides, starches, starch or dextrin ethers, in an amount of 0.15 to 30 wt%, a freezing point depressant, preferably selected from among chlorides in an amount of 5 to 30% and water in a make-up amount up to 100%. This document does not mention the low molecular weight carbohydrate fraction (which is a critical feature of the present invention) and does not suggest the benefits that could be obtained by its use.

The substances reported by Janke et al., Toth et al. and Bloomer, usually used in conjunction with salt, are found in nature and include hundreds (if not thousands) of ingredients such as complex carbohydrates, starches, sugars, proteins, etc.

The deicing solutions described above use agricultural by-products, for example corn-based soluble distillation products and soluble products obtained from the corn wet milling process. These naturally derived substances, which also include brewers condensed solubles (BCS), are characterized by extremely variable composition, viscosity, film-forming properties, pour point, pH, etc., and consequently also have a variable effectiveness when used in anti-icing solutions. Depending on the source of their origin and the specific batch of material, these substances, at low temperatures, sometimes do not lend themselves to free flow at times, that they cannot be evenly distributed over the road surface or mixed with chloride, which in turn causes that they become practically useless.

The solutions disclosed in the above patents also use materials that include highly undesirable or redundant components, which has certain difficulties for manufacturers and users, such as layering.

During storage, biodegradation, odor, clogging of filters and spray nozzles, and also with an adverse impact on the environment, for example due to high biochemical oxygen demand due to a very high content of organic substances (approx. ), the presence of phosphorus compounds and heavy metals.

In order to improve the quality and efficiency of operation, and at the same time meet the applicable standards, it becomes necessary to immediately introduce synthetic, chemically modified thickeners and carefully purified substances that could replace the agricultural by-products used today. The new formulation should be more effective, less toxic and allow for a reduction in the intensity of the corrosion of metals and concrete crushing, and should also take into account the problems of environmental pollution.

Accordingly, it is an object of the present invention to provide a deicer composition that meets elevated standards of performance while overcoming the above-described problems.

It is a further object of the present invention to provide a deicer composition which utilizes the synergistic effect of a combination of a low molecular weight carbohydrate and a freezing point depressant inorganic.

It is a further object of the present invention to provide a deicer composition which uses a low molecular weight carbohydrate to improve the melting performance of ice and which reduces the severity of corrosion.

It is a further object of the present invention to provide a deicing composition that has constant chemical and physical properties, which ensures consistent quality and effectiveness.

Another object of the present invention is to provide an economical and highly effective deicing composition.

The present invention is based on the finding that the use of low molecular weight carbohydrates (about 180 to 1000) in combination with an inorganic freezing point depressant such as chloride has a synergistic freezing point depressant effect. The anti-icing / anti-icing composition comprises carbohydrates with a molecular weight below about 1000 such as glucose / fructose, disaccharides, trisaccharides, tetrasaccharides, pentasaccharides, hexasaccharides, and mixtures thereof. A broader range of molecular weight for carbohydrates is from about 180 to about 1500 with about 180-1000 being preferred.

Accordingly, the deicing and anti-icing composition of the present invention is characterized in that it comprises an aqueous solution containing a low molecular weight carbohydrate and at least one substance from the group consisting of sodium chloride, magnesium chloride and calcium chloride as the inorganic depressant. pour point, and the ingredients of the composition are present in the following amounts:

% by weight

Carbohydrate 3 to 60

Freezing point depressant inorganic substance 5 to 35

A supplemental amount of water, the molecular weight of the carbohydrate being in the range 180-1500 and preferably in the range

180-1000.

The amount of carbohydrate in the composition according to the invention is preferably 5-30%.

In a preferred embodiment, the inventive composition further comprises a thickening agent in an amount of from 0.15 to 10%, and a viscosity range of 1 • 10 • 10 -3 ^{-2 -1} Pa • s (0.1-3 poise) at 25 ° C .

The thickening agent is selected from the group consisting of cellulose derivatives and high molecular weight carbohydrates, which for cellulose derivatives is from 60,000 to 1,000,000 and for carbohydrates from 10,000 to 50,000.

Preferably the carbohydrate is selected from the group consisting of glucose / fructose, disaccharides, trisaccharides, tetrasaccharides, pentasaccharides, hexasaccharides, and mixtures thereof.

The composition according to the invention may also contain a dye indicating the location of its distribution on a given surface.

PL 204 586 B1

Thus, the basic composition of the compositions of the present invention comprises the following two components in an aqueous solution, depending on weather, terrain, type and amount of ice and snowfall, and finally taking into account the environmental risk:

(1) inorganic freezing point depressants in the form of magnesium chloride, calcium chloride and sodium chloride; it is also possible to use metal acetates, for example calcium magnesium acetate;

(2) low molecular weight carbohydrates in the range 180 to 1500 (and preferably 180-1000); these carbohydrates can be obtained from agricultural produce, in the processing of corn, wheat, barley, oats, sugar cane, sugar beet etc. and optionally a third ingredient;

(3) thickeners, which are used in specific applications as the third primary ingredient to increase the viscosity of the composition so that it remains in contact with the road surface or solid particles in the rock salt / sand or rock salt / aggregate noise and finally only salt, sand or aggregate.

Thickeners are primarily cellulose derivatives or high molecular weight carbohydrates. The typical molecular weight of cellulose derivatives for methyl cellulose and hydroxypropyl methyl cellulose is in the range of about 60,000 to 120,000 and for hydroxyethyl cellulose in the range of about 750,000-1,000,000. Molecular weight of carbohydrates in the range of about 10,000-50,000.

The ingredients described herein provide a deicing and anti-icing composition with more consistent, batch-to-batch properties, while being a more effective deicer.

As the work of the present invention progressed, it was found that the main organic matter in the prior art mixtures described above was carbohydrate. In one test run, the BCS substance that was selected as the test sample was diluted in water and then divided into several fractions by adding increasing amounts of the ethanol / methanol mixture in the ratio 85/15 v / v. The characteristics of the various fractions and their freezing points when mixed with 15% magnesium chloride are summarized in the table below.

T a b e l a 1

A sample Added ethanol / methanol% Solid% Carbohydrate% Temperature of solidification ° F ° C BCS zero 43.6 43.1 -31.9 -35.5 Sediment - fraction A 60 5.3 3.8 -10.1 -23.4 Sediment - fraction B 74 3.7 3.2 -10.8 -23.8 Sediment - fraction C. 82 2.8 2.1 -10.3 -23.5 Sediment - fraction D 85 1.3 0.6 -9.9 -23.3 Dissolved solid - fraction E 85 30.7 29.8 -22.7 -30.4

Fraction A consisted of high molecular weight substantially insoluble polysaccharides, while fractions B to D contained sticky residual polysaccharides. Fractions A to D had virtually no effect on lowering the freezing point. On the other hand, fraction E, the largest component, had a significant effect on lowering the freezing point; it is a mixture of lower molecular weight polysaccharides.

Fraction E was also tested for ice melting properties at 25 ° F (-4 ° C) when mixed with magnesium chloride using the SHRP H-205.2 test (the so-called ice dissolution test for liquid deicers).

PL 204 586 B1

T a b e l a 2

De-icing solution Weight in g of molten ice per g of inorganic salt 15% magnesium chloride, control 16.9 BCS / MgCl2 18.2 E / MgCl2 fraction 19.3 32% calcium chloride 7.3 26.3% sodium chloride 7.5

The last two values were calculated based on the data from the SHRP H-205.2 test. The obtained results indicate a significant improvement of the melting properties in comparison with the commonly used sodium and calcium chlorides when the E and BCS fractions are mixed with magnesium chloride. In the case where fraction E was used, an improvement of 14% was also observed over the control substance. All of this, combined with the improvement in freezing point depressurization, shows that it is possible to obtain a significantly improved deicer.

The next stage of the research was to isolate and determine the active ingredients of BCS. This was done by first filtration using a 0.45 μm membrane followed by ultrafiltration using the Model UFP-lEs (A / G Technology Corporation, Needham, USA) with a molecular cutoff of 1000, and finally by gel permeation chromatography (GPC) using a Waters LC Module 1 with a set of three ultrahydrogel columns and 50 mm Na2HPO4 pH = 7 as mobile phase. The BCS solution comprised two major carbohydrate fractions, i.e. (a) a low molecular weight fraction where most of the components were below 1000 MW, and (b) a high molecular weight fraction containing 12,600 MW components as well as some components having a molecular weight in the range of 1,000-10,000. The chromatographic profile of fraction E was found to be very similar to that of the low molecular weight fraction (a), i.e. less than 1000. The DCS cane sugar solution contained more components than the BCS but had similar high and low molecular weight fractions with a similar molecular weight distribution .

To show that the low molecular weight fraction had the greatest freezing point lowering effect, successive series of freezing point measurements were performed using Jordan's Dead Sea Salt Solution instead of lab-grade magnesium chloride. Again, the concentration of magnesium chloride for each sample is 15% by weight.

T a b e l a 3

A sample Temperature of solidification ° F ° C Control: industrial grade magnesium chloride / water solution -0.4 -18.0 BCS -31.9 -35.5 GPC, high molecular weight fraction -5.1 -20.6 GPC, low molecular weight fraction -16.4 -26.9 BCS, fraction E -13.4 -25.2

Thus, it was shown that carbohydrates with low molecular weight (less than 1000) had the greatest effect in lowering the freezing point. Based on the experiments performed, it has been found that the deicer / anti-icing mixture should include components with a molecular weight of less than 1000, such as those listed in Table 4 below.

PL 204 586 B1

T a b e l a 4

Carbohydrate Molecular weight Glucose / fructose 180 Disaccharides 342 Trisaccharides 504 Tetrasaccharides 666 Hexasaccharides 990

There is a wide range of carbohydrates available on the market with different compositions. Simple sugars, disaccharides, and polysaccharides are listed below in terms of the effect of molecular weight and solute concentration on the freezing point. The concentration of magnesium chloride used in the tests was 15% by weight. The results for simple and complex carbohydrates are summarized in Tables 5 and 6, respectively.

T a b e l a 5 Simple carbohydrates

Carbohydrate Carbohydrate concentration% Temperature of solidification Type Name ° F ° C Control MgCl2 (15%) Zero -4.7 -20.4 Sugar Fructose 25.0 -8.9 -22.7 Sugar Fructose 50.0 -18.2 -27.9 Sugar Fructose 75.0 -31.9 -35.5 Sugar Glucose 30.0 -11.4 -24.1 Sugar Glucose 65.0 -37.3 -38.5 Disaccharide Maltose 25.0 -8.3 -22.4 Disaccharide Lactose 25.0 -11.7 -24.3

T a b e l a 6 Complex carbohydrates

Carbohydrate Carbohydrate concentration% Temperature of solidification Comments ° F ° C Control, MgCl2 (15%) zero -4.7 -20.4 Corn syrup - high content. maltose thirty -5.6 -20.9 It contains glucose, maltose and maltotriose Corn syrup - high content. maltose 65 -19.1 -28.4 Starch syrup, solid DE20 25.0 -9.9 -23.3 Average molecular weight 3746 Starch syrup, solid DE44 25.0 -11.6 -24.2 Average molecular weight 1120 Starch syrup, solid DE44 50.0 -21.3 -29.6 Starch syrup, solid DE44 65.0 -27.0 -32.8

PL 204 586 B1

From the above results it can be seen that the use of glucose is more preferable than fructose, and of the two disaccharides the use of lactose is slightly more preferable than maltose. Corn syrup DE20 contains about 47% mono- to hexasaccharide sugars, and DE44 contains about 69%, with the use of the latter substance being slightly more advantageous with regard to freezing point depression. The data in Table 6 also show that there is a relationship between the carbohydrate concentration and the freezing point, which allows obtaining substances with different properties.

More complex carbohydrates, such as dextrins and maltodextrins, obtained by the hydrolysis (enzymatic or with dilute inorganic acids) of corn starch were also tested. A series of thickeners were also tested. In addition, a control solution of magnesium chloride obtained from the hexa-hydrate was prepared and the results are summarized in Table 7. Again, the magnesium chloride concentration for each sample is 15% by weight.

T a b e l a 7

Relationship Concentration% Temp. clotting Comments ° F ° C Control, 15% MgCl2 zero +3.4 -15.9 Dextrin 5.0 -4.7 -20.4 Maltodextrin DE5 5.0 -4.7 -20.4 Maltodextrin DE15 9.1 -17.1 -27.3 Molecular weight lower than DE5 Hydroxyethylcellulose 250 HHR 0.33 + 1.2 -17.1 thicken agent Carboxymethylcellulose 1.0 +2.5 -16.4 thicken agent Arabic gum 3.6 -1.8 -18.8 thicken agent Gum tragacanth 470 0.2 -3.3 -19.6 thicken agent

For maltodextrin DE15 good results have been obtained due to the content of lower molecular weight components and the higher concentration. Increasing the molecular weight reduces the effect on the freezing point. Certain thickeners have been found to be unstable in the presence of magnesium chloride, such as for example carboxymethylcellulose, as a result of which their thickening efficiency has decreased.

It is also important to determine the chloride content of the deicing / antifreeze fluids. An increase in the chloride content means a drop in the freezing point and an improvement in the melting properties of ice. These properties are summarized in Table 8 for MgCl2 and CaCl2 at different salt and carbohydrate concentrations.

T a b e l a 8

Chloride Salt wt.% Carbohydrate wt.% Temperature of solidification ° F ° C MgCl2 22.7 18.0 less than -47 less than -43.9 MgCl2 15.0 25.5 -22 -thirty CaCl2 29.6 18.6 less than -47 less than -43.9 CaCl2 17.5 4.1 -5.4 -20.8 CaCl2 15.0 4.1 -0.6 -18.1

PL 204 586 B1

As the concentration of salt and carbohydrates increases, the freezing point of the mixtures decreases. In the case of calcium chloride, for the carbohydrate concentration set at 4.1%, an increase of 2.5% by weight. CaCl2 caused the freezing point to drop 4.8 ° F (2.67 ° C). The composition of the substance can vary depending on local conditions. Particular attention should be paid to the salt concentration when it approaches the eutectic point on the curve, freezing point, where the freezing point increases and the salt may precipitate as crystals.

Based on the above considerations and laboratory tests, it was found that the basic composition of the composition includes the following two components in an aqueous solution, depending on weather and terrain conditions, the type and amount of ice and snowfall, and finally taking into account the risk to the environment:

(1) an inorganic freezing point depressant in the form of inorganic electrolytes such as sulfates and acetates and other substances at a concentration of 5 to 35 wt%; the main types used include magnesium chloride, calcium chloride and sodium chloride.

(2) a carbohydrate, especially low molecular weight carbohydrates in the range of about 180 to 1500; the preferred range is 180-1000; These carbohydrates can be obtained primarily from a number of agricultural products, in the processing of corn, wheat, barley, oats, sugar cane, sugar beet, etc.

(3) an optional third component is: thickeners used at a concentration of about 0.15 to 10 wt.%. to increase the viscosity of the substance so that the substance remains in contact with the road surface or solid particles in the noise rock salt / sand or rock salt / aggregate, and finally the salt itself, sand or aggregate.

Thickeners are primarily cellulose derivatives such as methyl cellulose (e.g. Methocel), hydroxyethyl cellulose, hydroxypropyl methyl cellulose, hydroxypropyl cellulose etc. or high molecular weight carbohydrates.

The corrosivity of anti-icing / anti-freeze fluids is important due to the effect they have on cars and other vehicles, bridges, concrete reinforcement bars, such as bridge drives, driveways, and multi-storey garage roadways.

Testing fluids for corrosivity can be quite complicated; it uses tests developed by organizations such as ASTM and the National Association of Corrosion Engineers (NACE). Test conditions and metals should be similar to those encountered in practice; We are talking here, for example, about oxygen conditions and samples of cold-rolled steel. The prior art tests, using nails immersed in a liquid contained in a screwed bottle, are not reliable due to the lack of oxygen, changes in the composition of metal substrates, the degree of cold working and the degree of cleanliness.

Notable tests include SHRP H205.7 Test Method for Evaluation of Corrosive Effects of Deicing Chemicals or Metals (Handbook of Test Methods for Evaluating Chemical Deicers SHRP-H332, Strategic Highway Research Program, National Research Council, Washington, USA) and test described in Deicer Specifications for the Pacific Northwest States of Idaho, Montana, Oregon, Washington. The latter is based on the NACE Standard Test Method for the Laboratory Corrosion Testing of Metals. TM0169-95.

Some results on the rate of corrosion using the SHRP H205.7 test, demonstrating inhibition of this process by carbohydrates, are summarized in Table 9 below.

T a b e l a 9

Chloride% Carbohydrate% Corrosion rate Miles per year Kilometers per year 1 week 3 weeks 6 weeks 1 week 3 weeks 6 weeks 15% NaCl Zero 5.97 4.66 5.48 9.61 7.50 8.82 15% MgCl2 Zero 2.58 1.93 1.73 4.15 3.11 2.78 15% MgCl2 4.1 0.89 0.61 0.40 1.43 0.99 0.64

PL 204 586 B1

From the results summarized in Table 9, it can be seen that the carbohydrate-magnesium chloride composition reduces the corrosion rate of steel by 92.7% compared to sodium chloride alone and by 76.9% compared to magnesium chloride alone. The compositions of Examples 3 and 4 were tested for corrosivity using the Pacific Northwest States protocol and showed a reduction in the corrosion rate compared to sodium chloride solution of 57.2% in Example 3 and 40.4% in Example 4. This also shows that these compositions are inhibiting the course of corrosion.

The following are exemplary compositions of the present invention that are useful as deicing agents:

P r x l a d I Component

Parts by weight

22.5

50.0

2.0

0.5

25.0

-12.5 ° F / -24.7 ° C 10 ^-2 Pa ^ s (20 cP) clear golden solution mild, pleasant

Solid starch syrup DE44 Magnesium chloride solution * industrial grade 2% Methocel solution

Dye (Caramel YT25)

Water

Pour point (ASTM-D 1177-94)

Viscosity at 77 ° F / 25 ° C:

Look:

Smell:

* Note: The industrial grade magnesium chloride solution is a commercially available magnesium chloride solution, also containing calcium chloride, sodium chloride and potassium chloride.

P r z x l a d II

Ingredient

High Maltose Corn Syrup Industrial Grade Magnesium Chloride Solution Dye (Caramel YT25)

Water

Pour point (ASTM-D 1177-94) Viscosity at 77 ° F / 25 ° C:

Look:

Smell:

P r z x l a d III

Ingredient

High maltose corn syrup. Magnesium chloride solution of industrial quality. Water

Pour point (ASTM-D 1177-94) Appearance:

Smell:

Relative density:

Viscosity at -94 ° F / -70 ° C

P r x l a d IV

Ingredient

High maltose corn syrup

43% CaCl2

Water

Pour point (ASTM-D1177-94) Appearance:

Smell:

Relative density:

Viscosity at -470F / -43.9 ° C:

P r z k ł a d V

Ingredient

High fructose corn syrup

Parts by weight

31.5

50.0

0.5

18.0

-22 ° F / -30 ° C

1.44-10 ^-2 Pa. S (14.4 cP) Clear, golden solution, mild, pleasant

Weight parts:

22.2

70.0

7.8 below -47 ° F / -43.9 ° C clear, light brown, mobile liquid mild, pleasant 1.27 heavy syrup, fluid

Weight parts:

20.5

72.3

7.2 below -47 ° F / -43.9 ° C clear, colorless, moving fluid mild, pleasant

1.33 very heavy syrup

Weight parts:

19.55

PL 204 586 B1

43% calcium chloride solution Water

Pour point (ASTM-D1177-94) Appearance:

Relative density:

Smell:

73.15

7.30

-31 ° F / -35 ° C clear, colorless, moving liquid 1.38 mild, pleasant

P r x l a d VI

Ingredient

Glucose

Industrial Grade Magnesium Chloride Solution 2% Methocel Dye Solution (Caramel YT25)

Water

Pour point (ASTM-D1177-94) Appearance:

Smell:

Weight parts:

32.5

50.0

2.0

0.5

15.0

-38.2 ° F / -39.0 ° C clear, golden solution, mild, pleasant

The dyes are used to enable it to be established during application where a given deicer has already been scattered. Among the non-toxic dyes, caramel solutions and food-grade dyes can be used.

The present invention is detailed with reference to various preferred embodiments. It should be understood that a person skilled in the art can make various changes to the elements of the invention without departing from the scope of the invention as defined in the claims.

Claims (7)

A deicing and anti-icing composition comprising an aqueous solution comprising a low molecular weight carbohydrate and at least one of the group consisting of sodium chloride, magnesium chloride and calcium chloride as an inorganic freezing point depressant, wherein the components are: of the compositions are present in the following amounts: Carbohydrate Freezing point depressant inorganic substance Water% by weight 3 to 60 5 to 35 in supplemental amount wherein the molecular weight of the carbohydrate is in the range 180-1500. 2. A composition according to claim 1 The carbohydrate of claim 1, wherein the carbohydrate has a molecular weight in the range 180-1000. 3. A composition according to p. 1 or 2, characterized in that it additionally comprises a thickening agent in an amount of from 0.15 to 10% and has a viscosity in the range of 1 • 10 • 10 -3 ^{-2 -1} Pa • s at 25 ° C. 4. A composition according to p. The process of claim 3, characterized in that the thickening agent is selected from the group consisting of cellulose derivatives and high molecular weight carbohydrates, which for cellulose derivatives is from 60,000 to 1,000,000 and for carbohydrates from 10,000 to 50,000. 5. A composition according to p. The composition of claim 1, 2 or 4, characterized in that it comprises a carbohydrate selected from the group consisting of glucose / fructose, disaccharides, trisaccharides, tetrasaccharides, pentasaccharides, hexasaccharides and mixtures thereof. 6. A composition according to p. 5. The composition of claim 3, having a carbohydrate content of 5-30%. 7. The composition according to p. 3. The method of any of the preceding claims, further comprising a dye indicating the location of its distribution on the surface in question.